Grinding head and grinding surface therefor



S. C. RALYS July 15, 1958 GRINDING HEAD AND GRINDING SURFACE THEREFOR Filed April 30, 1956 2 SheetsSheet 1 FIG. 6

INVENTOR.

STANLEY C. RALYS Mew! ATTORNEY July 15, 1958 S. C. RALYS GRINDING HEAD AND GRINDING SURFACE THEREFOR Filed April 30. 1956 2 Sheets-Sheet 2 INVENTOR. STANLEY C. RALYS ATTORNEY gait GRHNBHIQ HEAD AND GRINDTNG SURFACE THEREFOR Stanley C. ltaiys, @range, Mass, assignor to Leavitt Machine Company, Grange, Mass a corporation of Messachusetts Application April so, was, Serial as. 581,481 I 2 Claims. or. 51-197 valve grinding head to seat a readily replaceable abrading race.

Another object of the'invention is the provision of an improved valve grinding head having an improved re placeable grinding surface.

The accompanying drawings illustrate the invention by reference to the grinding head of a gate valve grinding machine.

in the drawings: I

Fig. 1 is a perspective view of the valve grinding head and its driving shaft shown broken awat;

Fig. 2 is a section taken on line 22 of Fig. 1 looking in the direction of the arrows;

Fig. 3 is a section taken on line 3-3 of Fig. 2 looking in the direction of the arrows;

Fig. 4 is an exploded view of the grinding disc head shown in Fig. 1;

Fig. 5 shows the blank from which the abradant member is preformed;

Fig. 6 is a face elevational view of the preformed abradant member;

Fig. 7 is a front face view of a modified head;

Fig. 8 is a fragmentarysection taken on line 8-8 of Fig. 7; and v Fig. 9 is an exploded view of another modification.

The invention has been illustrated in an embodiment which was devised as to itsjdetails, specifically for a machine for grinding gate valves, it being understood that the invention is not intended to be so limited unless and only to the extent called for by the specific language of the claims.

Upon reference to the exploded view of Fig. 4 it will be observed that the grinding head 10 (see'Fig. 1) is comprised of the grinding disc 12 having a central opening 14 and a separable abrasive facing section 16 having a central opening 18. It will be observed further that the central opening 14 of the grinding disc is threaded and dimensioned to receive one end of a driving shaft 11 as shown in Fig. 1. v

The grinding disc 12 is shown having areas of the working face thereof reduced in thickness to thus provide a plurality of spaced apart depressions 20 which extend radially of the disc. These depressions are shown as defined by bottom wall 22, rear wall 24 and opposed sidewalls 26 so as in effect to provide compartments open at their front end at the perimeter of the disc and Which terminate at their rear ends short of the central opening 14 to leave the hub portion 27. These depressions may be provided in the disc in any preferred or desired manner and the broad aspects of the invention do not require coincide. the attainment of the broader objects of the invention.

the drawings.

2, 12,904 Patented July 15, 195 8 that they be contoured or dimensioned precisely as shown in the drawing.

The depressions 20in turn define spaced apart areas 30 which are relatively elevated and the faces of which are presented in the working plane which is shown flat in the illustrative embodiment. The relative widths of the depressions 2t) and the elevated areas. 3%], measured along the perimeter of the disc, can be varied within permissible limits for effecting the general objects of the invention.

The abrading section16 is made preferably of a relatively thin and flexible sheet material having one of its faces provided with grit or abradant. This section is shown preformed in Fig. 4 to provide depressed areas 40 and the relatively elevated areas 42. It will be observed from the various figures of the drawings that the width or diameter of abrading section 16 is shown as approxi mating that of the disc 12 so that their perimeters will While this is preferred it is not essential for It will be further observed that the central opening 18 of section 16 is larger than the central opening 14 of the disc 12. and that the depressions 40 of the abrading section 16 are shown as correspondingin transverse crosssection to that of depressions 20 of the disc 12 so that the former can be received to. seat in the latter. The depth of the depressed areas 40 measured radially, is shown as less than that of depressions 2,0 of the disc because central opening 13 of abradant section 16 is larger than that of disc 12.

For convenience of reference, numeral 50 has been applied to the bottom walls of depressions 49 of abradant section, 16 and numeral 52 has beenapplied to the sidewalls thereof, it being observed that the depressed areas of member 16, unlike the depressions 2d of disc 10, are ope at both front and rear.

It will be observed from what has been said above that the invention contemplates that the abradant section 16 be assembled with the disc to seat its relatively elevated areas 42 on the relatively elevated areas 30 of the grinding disc 12 and to seat its depressed areas 40 in the depressions 20 of that disc, and the manner of assembly thereof is so shown in Fig. 1 of the drawing.

It is desirable that means he provided for retaining these two components of the grinding head in assembled relation and to this end preferred means are shown in These means comprise openings 54 through the bottoms 22 of depressions 20 of disc 12 and similar openings 56 through the bottoms 59 of depressions 40 of abradant section 16, these sets of openings being located in the respective bottoms so as to register when the abradant section is fully seated on the disc as shown in Fig. 1. These openings, when registered, re ceive therethrongh headed members 60 (see Figs. 3 and 4) having spreadable prongs 62 which are bent apart and countersunk into depressions66 in the rear face of disc 12 and over spacer members 68 (see Fig. 2).

The abrading section 16 has been hitherto referred to as being preformed because of the advantage resulting therefrom in assembly and replacement. it will be understood, however, that this section can be given its formation when and as it is assembling with disc 12, reference being had to Fig. 5 of the drawings which shows the blank '73 before it is preformed and whichv could be employed for shaping the blank about the disc to arrive at the assembly of Fig. 1.

It will be observed that the blank shown in Fig. 5 larger than it is after being preformed and that its central opening is larger than that of the latter. This results from its preformation.

The grinding head shown in Fig. 1 seats the relatively elevated areas 42 of the abrasive section 16 directly on the relatively elevated areas 3 of the grinding disc 12.

The modification shown in Fig. 8 interposes a yieldable cushion 74 therebetween, the cushion shown in that figure being dimensioned and contoured to seat in matching relation on the elevated areas 30 of the disc 12 and preferably permanently secured thereto. Cushion 74, where used, may alternatively be secured to the abrasive section 16, or be free of securement to either.

Reference will now be made to the modification shown in Fig. 9 which is directed to simplifying the procedure for arriving at the formation of disc 12. This procedure contemplates that it be formed from two sections, 80 and 82. Section 80 is imperforate except for the central threaded opening 84 and the three fastener receiving openings 86. The member 82 is likewise provided with a threaded central opening but differs from disc 80 in that it lacks the openings 86 and has its perimctcrcut away for spaced apart areas 88. The two discs 80 and 82 are of the same diameter, their central openings are also of the same diameter, and the threads formed in said opening match so that when the discs are united they form a continuity with the openings 88 of disc 80 located properly in the spaces 86 which may be done in any preferred or desired manner, the matching threads to thus arrive at the disc of Fig. 1. This modification has been described because it is a preferred way of making the aforementioned disc.

What is claimed is:

1. A rotatable grinding head for avalve grinding machine comprising a circular backing disc mounted on the forward end of a rotatable shaft and having a front face provided with a plurality of circumferentially equidistant radial depressions of generally rectangular prismatic shape each having a flat bottom wall bounded by a pair of parallel spaced opposite side walls of rectangular shape lying in planes which intersect the front face of the disc at 90, said side walls defining the leading and trailing edges of flat coplanar elevated areas forming the working face of the disc, said edge of each of said areas lying in planes which intersect radially outwardly of the axis of the shaft, an abrading section comprising a sheet having a front face coated with abradant material and being preformed with portions fitting the depressions, side walls and elevated areas respectively of the backing disc, and a headed fastening member secured in registering openings in the bottom wall of each depression and the depressed portion of the abrading section for cooperating with the side walls of the depressions and the portions of the abrading section engaged therewith to connect the section to the disc securely against relative movement during rotation while the section is in grinding engagement with a valve.

2. The combination claimed in claim 1 in which the backing disc comprises a continuous rear member and a front member having generally radially extending rectangular portions cut out to provide openings extending through the periphery of the member, said members being secured together so that the front face of the rear member forms the bottom walls of the depressions and the side wall of the cut out portions of the front member form the side walls of the depressions.

References Cited in the file of this patent UNITED STATES PATENTS 384,076 Riedell June 5, 1888 421,763 Rogers Feb. 18, 1890 1,964,240 Beard June 26, 1934 1,999,922 Beard Apr. 30, 1935 2,085,280 Tyler June 29, 1937 2,133,612 Gallivan Oct. 18, 1938 2,394,064 Anstutz Aug. 25, 1942 2,332,676 Stetler Aug. 25, 1942 

